Hitherto the generation a homogeneous and stable homeotropic orientation of liquid-crystalline phases was technologically fairly difficult. For instance, the liquid-crystalline phase used was doped with surface-active substances, such as lecithins, long-chain aliphatic amines, quaternary ammonium or phosphonium salts or carboxylatochromium complexes (Appl. Phys. Lett. 27,268 (1975)). It was also customary to coat glass surfaces with said substances before introducing the liquid-crystalline phase. However, the uniformity and stablility of the resulting homeotrophic orientation of liquid-crystalline phases leave something to be desired.